In recent years, electronic equipment including a mobile phone and a personal computer have been more compact but more sophisticated. In such a trend, as for the housing of electronic equipment, a foldable housing, which is formed of a stationary structure having a movable part foldably equipped therewith, has become popular. As a demand of the foldable housing, a folding device with ease in operation is now sought.
Now will be described a prior-art folding device and electronic equipment using the device, with reference to FIGS. 9 through 12C.
FIG. 9 shows a sectional view of a prior-art folding device, and FIG. 10 shows an exploded perspective view of the device. Generally cylindrical-shaped movable case 2 made of resin has through-hole 2B at its center, and through which cylindrical portion 1B of metallic movable shaft 1 is inserted. Edge portion 1A of movable shaft 1 contacts with stepped portion 2A formed on the right side of movable case 2, preventing shaft 1 from rotating in case 2. Metallic movable part 4 has generally oval-shaped through-hole 4A at its center. Holding portion 1C of movable shaft 1 is inserted in through-hole 4A, whereby movable part 4 is supported movably for axial motion with respect to shaft 1. At the same time, movable part 4 is urged in the axial direction by spring 3. Metallic wire spring 3 is accommodated, being somewhat compressed, in the interior of movable case 2. Metallic stationary part 6 has through-hole 6A at its center. The tip of cylindrical portion 1B of shaft 1 is rotatably inserted in through-hole 6A. Movable cams 5A and 5B are disposed on movable part 4 to provide click-stopped folding. Cam 5A resiliently contacts with stationary cam 7A of stationary part 6, while cam 5B disposed opposite to cam 5A contacts with stationary cam 7B of part 6. Holder tip 1D of movable shaft 1 is inserted through case 2, movable part 4, and stationary part 6, and then fixed by metallic C-ring 8. Stationary part 6 rotatably holds movable shaft 1, movable case 2 and movable part 4. In this way, the whole structure forms folding device 9.
Next will be described electronic equipment using such structured folding device 9, with reference to FIGS. 11A-C showing a side view of the equipment. Stationary housing 41 made of electrical insulating resin has operating section 43 on its upper surface. Operating section 43 is formed of a plurality of keys. On the other hand, movable housing 42, which is also made of electrical insulating resin, has display 44 including a liquid crystal display (LCD) on its surface. Stationary part 6 of folding device 9 is mounted on one end of stationary housing 41, while movable case 2 of device 9 is mounted on one end of movable housing 42. As a result, folding device 9 holds housing 42 so as to be foldable over housing 41.
Now will be described the folding motion in the folding device structured above and electronic equipment using the device, with reference to FIGS. 11A through 12C. Firstly, the explanation is given on the “folded” state, as shown in FIG. 11A, in which the surface of movable housing 42 is folded over the upper surface of stationary housing 41. In folding device 9 shown in FIG. 12A, movable cam 5A of movable part 4 urged by spring 3 engages with stationary cam 7A of stationary part 6, maintaining two housings 41 and 42 in the folded status. When a user rotates housing 42 by hand against the spring-urged force in a direction that housing 42 is raised from housing 41, cam 5A of movable part 4, via movable case 2 held by movable housing 42, rotatively moves against the spring-urged force toward ramp 7C. Next, the explanation is given on the process to the “half-opened” state as shown in FIG. 11B. The user further rotates housing 42 until it stands nearly vertical to stationary housing 41. As shown in FIG. 12B, when the rotating motion rotates movable part 4 via movable case 2 with respect to stationary part 6 of device 9, movable cam 5A rotatively moves onto flat portion 7D on the upper surface of stationary part 6. Further rotating motion brings two housings 41 and 42 in the “full-opened” state, as shown in FIG. 11C. At the moment, movable cam 5B disposed opposite to cam 5A engages with stationary cam 7A, maintaining two housings 41 and 42 in the full-opened state as shown in FIG. 12C. To fold movable housing 42 over housing 41, the user reversely rotates housing 42 by hand. The folding operation of housing 42 is thus structured.
In the prior-art folding device and the electronic equipment using the device, however, there have been some inconveniencies—when opening up housing 42 from its “folded” state, the user has to flip it up against the force urged by spring 3. Therefore, stationary housing 41 has to be held with one hand, while movable housing 42 is flipped up (unfolded) with the other. The fact that the flip-up (unfolding) motion cannot be done as a one-hand operation may not be user-friendly.